Onibi

Also Known As: 鬼火, “demon fire”; also written 燐火 rinka; regional names include igebo in Mie, asobibi in Tosa, kazedama in Gifu, watari-bishaku in Kyoto, hidama in Okinawa
Region/Culture: East Asia
Mythos: Japanese Mythology
Primary Type/Nature: Elementals
Mythical Attributes: It splits into many flames and gathers back into one, drifts against the wind at about head height, and in the older accounts draws the vital essence out of anyone who comes close.
Role in Mythos: Onibi is the general Japanese name for the mysterious fires that rise from the dead, the umbrella under which dozens of named local ghost-lights are gathered.
Relation to Humans: Most onibi do nothing but burn and drift, and country people treated them as weather rather than as a threat. The older written tradition is harsher, describing fires that approach the living to feed on their vitality, and a few regional types that set roofs alight.

Rain on a Japanese summer night has a smell to it, wet earth and cut grass and the cold iron of a river running high. That is the weather the fires come in. They collect over marshland and graveyards and the flooded edges of paddy fields, one or two at first, then twenty, then thirty, hanging at about the height of a walking man’s face and drifting without any wind to carry them. Some are no larger than a candle flame. Some are the size of a person. Most of them burn blue.

Onibi means demon fire, and the name covers a great deal of ground. Before it was a creature it was a category, the word Japanese used for any unexplained light that behaved as though it had intentions. The oldest description that carries real weight sits in the Wakan Sansai Zue, the illustrated encyclopedia Terajima Ryōan compiled in 1712. He writes of a blue light like the flame of a pine torch, which scatters into several and gathers again into one, and which comes near living people to draw off their vital breath. From the proportions of his woodcut, later readers worked out a size: two or three centimetres across at the smallest, twenty or thirty at the largest, floating a metre or two off the ground.

Where they come from depends on which tradition is speaking. The Wakan Sansai Zue gives a battlefield answer. Blood from slaughtered men and horses and oxen soaks into the ground, lies there through long years, and eventually changes into spirit. Elsewhere the origin is simpler and more personal: a corpse, or a grudge. A resentment strong enough survives the person who held it and comes back as fire. Chinese texts from before the common era had already linked the same lights to the blood of humans and animals, and the Japanese word for them borrowed that vocabulary wholesale.

The most famous individual onibi began with a theft. At Mibu-dera, south of Saiin outside Kyoto, a monk named Sōgen spent years lifting coins from the offering box and siphoning lamp oil to sell in secret. He grew old, he died, and he went where such men go. On certain nights his face still comes up over the temple ground, an old man’s head wrapped in flame and twisted with pain, and the locals call it Sōgen’s fire of Suzaku. Toriyama Sekien drew him into the first of his yōkai picture-books in 1776, and the image fixed itself: not a light with a story attached, but a face burning.

Sekien went back to the same well three years later for the Sarakazoe, the plate-counter. That one is Okiku, the servant girl of the Banchō Sarayashiki tales, killed over a missing dish and thrown down a well. She rises out of it as an inka, a shadow-fire, and the counting comes with her. One. Two. Three. The count never reaches ten.

The regional record is stranger and less literary, and it is where the fires feel most like something people actually saw. In Tosa, in what is now Kōchi, the asobibi appeared over the castle town and out across the sea, close by one moment and far off the next, one flame breaking into several and reassembling. It never hurt anybody. In Watarai district in Mie they were called igebo. Around Ibigawa in Gifu the kazedama came in storms, a ball of light about the size of a serving tray, and in the great wind of 1897 it came out of the mountain and drifted across the sky again and again while the roofs came off below. In the mountain villages of Kitakuwada in Kyoto the watari-bishaku drifted through, a blue-white fire with a long thin tail that people compared to a ladle. Okinawa’s hidama lived in the ash pot behind the kitchen, took the shape of a bird, and flew out to set houses alight, which is a considerably less peaceful arrangement than a light over a graveyard.

The behaviour is consistent enough across all of them to look like a description of something. The fires appear from spring into summer, most often on wet nights. They favour water, wetland, forest, grassland, burial ground, though occasionally one turns up in a street. They divide and recombine. Some give no heat at all when touched. Others burn what they touch.

There is a moment recorded in the Mimibukuro, the collection of odd stories the Edo magistrate Negishi Yasumori kept over thirty years, in a section titled simply “On onibi.” A fire appeared above the mountains at Hakone. It split into two, and the two flew around each other in the dark for a while, and then they came back together, and then the single fire broke into many.

By the nineteenth century the explanation had shifted to chemistry. Phosphorus had been isolated in 1696, it was known to occur in the body, and Japanese writers from Arai Shūkichi onward settled on the idea that the phosphorus in a buried corpse was what burned above the grave. That reading held into the 1920s and made it into dictionaries. Then the bioluminescence researcher Kanda Sakyō took it apart in his 1931 study of the shiranui, the hitodama and the fox-fires, pointing out that the theory rested on a coincidence of characters and a misread Chinese source, and that a great many eyewitness accounts fit it badly or not at all. Marsh gas, phosphine, ball lightning and St Elmo’s fire have all been proposed since. Kanda’s own conclusion was that no single answer covers the whole record, and nobody has improved on it.

What an onibi can do is limited and specific. It moves without wind and against it. It multiplies and rejoins. It goes out and comes back. In the old encyclopedic accounts it can take the strength out of a person who approaches, and a few of the local types can burn a house down. What it cannot do is anything else. It does not speak, it does not shapeshift, it does not follow anybody home. It is bound to its ground and its season, and it goes out at dawn without being driven off.

Nobody has ever caught one.

The named ones can be laid, because they are grievances rather than phenomena. Sōgen burns because of what he stole, and Okiku counts because of the plate she never broke. Deal with the cause and the fire has no reason to keep burning. The nameless ones over the marshes have no such handle, and no ritual against them survives, because none was needed. They were never much of a danger. They were a thing you saw on the way home in the rain, and mentioned to somebody, and forgot.

Frequently Asked Questions

What is an Onibi?

Onibi is the general Japanese term for a mysterious floating fire, usually understood as a spirit that has risen from a human or animal corpse or from a powerful grudge. The name means “demon fire,” and it covers dozens of regionally named ghost-lights across Japan. Onibi typically appear as blue or blue-white flames hovering at about head height in graveyards, marshes, forests and grassland.

What is the difference between Onibi, Hitodama and Kitsunebi?

Onibi is the broadest of the three terms, used for mysterious fires in general. Hitodama refers specifically to the soul of a particular dead person leaving the body, and kitsunebi is fire produced by foxes to lead travellers astray. The three are frequently confused in practice, and because no one has ever established what any of them are, the boundaries between them were never firm.

When and where do Onibi appear?

Onibi are said to appear from spring through summer, most often on rainy nights. They favour wetlands, watersides, forests, grassland and graveyards, though they occasionally turn up inside towns. They usually hover a metre or two above the ground and can appear singly, in pairs, or in groups of twenty or thirty at once.

Are Onibi dangerous to humans?

Most onibi are harmless and do nothing but drift and burn, and some give off no heat at all when touched. The older written accounts are darker: the 1712 encyclopedia Wakan Sansai Zue describes onibi approaching living people to draw off their vital essence. A few regional types are genuinely destructive, such as Okinawa’s hidama, which was said to fly out in the shape of a bird and set houses on fire.

What is the most famous Onibi?

The Sōgenbi is the best known, a fire that carries the anguished face of a monk named Sōgen who stole offerings and lamp oil from Mibu-dera temple in Kyoto and burns for it after death. Toriyama Sekien illustrated it in his yōkai picture-book of 1776. A close second is the Sarakazoe, the fire of the murdered servant Okiku rising from her well and counting plates.